In the automotive paint and refinish market, a number of different paints are manufactured to meet consumer demands and workflow goals. A refinish paint manufacturer will offer many different paint grades (lines) that will produce differing qualities of finishes on a vehicle. The manufacturer will also produce for use within each paint line, primer fillers, sealers, basecoats, single-stage topcoats, and clearcoats that are specifically designed to adhere to and to produce quality finishes with one another. More than one of each of the individual paint layers is typically, produced. For example, two different clearcoats generally may be used; one being a fast-drying clearcoat for use in repairing a small area and another being a slower-drying clearcoat that has very good visual appearance for use over a large portion of the surface being repaired, typically an entire body panel or the entire vehicle.
In general, each of these paint layers will consist of two (2K) or a three-components (3K) which must be mixed in the correct ratio prior to application. A 2K paint mixture consists of a first component which is generally the film-forming binder and other adjuvants. The second component, called the activator or activator package, is the crosslinker and its adjuvants. In refinish paint, the crosslinker is usually a polyisocyanate or a mixture of polyisocyanates. Within this second component, a paint manufacturer will have several activator packages which the application specialist will chose generally based upon the ambient spray conditions. The activator packages that the manufacturer supplies is most often chosen from a low temperature activator package for use when the ambient spray conditions are relatively cool, a medium temperature activator package, and a high temperature activator package for use when the ambient spray temperature is relatively high. Other activator packages may also be provided to further allow for spray condition latitude. While the activator packages have typically been formulated to conform to ambient spray temperatures, the application specialist has a certain amount of freedom in choosing which component to use depending upon the workflow and customer expectations.
In a 3K paint system, the first two components are the same as a 2K but this system adds a third solvent component, also called the reducer. The reducer is added if a mixture of the first two components, called a pot mix, is too viscous for the spray equipment. As with the activator packages, the reducer is chosen with ambient spray temperature in mind. For low temperature spray conditions, a reducer is chosen that is relatively volatile. For relatively high ambient temperature spray conditions, a reducer is chosen that is less volatile. A paint manufacturer may provide several reducer packages for the application specialist to choose from.
While an activator package may be useful for one layer such as the primer layer, different activator packages may have to be developed for each of the individual layers. To help alleviate the problem of different activator packages for each paint layer, some paint manufacturers have developed a series of common activator packages that can be used for more than one of the layers. However, the mixing ratio of the film-forming binder and the activator package in one layer is a different ratio than what is required for the other layers and, no paint system uses only one activator for all of the layers. Complicating this system even more is the fact that one layer may require a reducer while another layer will not use any reducer at all.
The refinish paint application specialist is required to consult multiple sources to make sure the correct mixing ratios are used, the correct activator package is added to the film-forming binder, and the correct reducer along with its corresponding correct amount is added if one is needed. In addition to all of these requirements, the shop owner must be sure that the application specialist has all of the correct components on hand to meet the demands of the job conditions.
The present invention is directed at a simplified paint system that uses a common activator for each of the layers and wherein all of the layers use the same binder to activator mix ratio and preferably, no reducer addition is required to form a sprayable pot mix. The invention allows the refinish paint application specialist to simplify the painting process. Preferably, in countries that use non-metric units, the paint system is formulated to have a binder to activator mix ratio of from about 8:1 to about 1:1, preferably from about 4:1 to about 1:1 and in countries that use metric units, the paint system can be formulated to a binder to activator ratio of from about 5:1 to about 1:1. This will also allow the shop owner to reduce the number of paint cans held in their inventory.